Our
Moon (Selene) is apparently lifeless. It is almost totally
dry. If water exists, this will be only in the form of
ice that has come from cometary impacts and this will only occur
near the poles, in deep shadow. There is no atmosphere,
so the Moon is in the vacuum of space. The surface temperatures
alternate between extreme heat and extreme cold, as day turns
to night and back again. It is also exposed to extremely
high levels of radiation. Overall the Moon appears to
be totally inhospitable towards life, even microbial life.
Even so, two
lunar rock samples recovered y Apollo 12 contained amino
acids. Where did these originate? Cometary impact
is the most likely explanation, though this is not proven.

(above) Lunar soil
and rocks from Apollo 12 are unloaded from an aircraft. November
1969The
discovery of archaea microbes deep in the Earth has led some planetary
scientists and microbiologists to re-think the idea of the Moon
as a lifeless world. Perhaps microbial life does exist on
the Moon several meters below the surface, from where samples
have never been collected. Earth rocks containing microbes
have undoubtedly reached the Moon. It is estimated that
several million tonnes of Earth rock has been ejected into space
since life gained a foothold on Earth, through meteorite, asteroid,
and comet impacts. Some of this material has certainly landed
on the Moon, and some of the material that landed almost certainly
contained microbial life. Whether it survived the trauma
of launch, space travel, landing and the lunar environment is
an open question, but it is something we should keep an open mind
about.